Aluminum wire cables are increasingly being incorporated in automotive wiring harnesses. There are several factors driving this trend. First, the market price of copper, traditionally used for automotive wiring, is significantly higher and more volatile than that of aluminum. Second, the weight of aluminum wiring is approximately half that of the equivalent copper wiring. The push for more fuel efficient vehicles is requiring weight to be taken out of the vehicle and aluminum-based wire cables provide a good opportunity to reduce weight by substituting aluminum cable for copper cable.
Aluminum does have some disadvantages in vehicle wiring. Aluminum cable typically has multiple strands in the wire cable to increase flexibility of the cable. Aluminum forms an oxide layer that has a lower conductivity than aluminum and is very hard. Because these aluminum oxides form almost instantaneously on the surface of the aluminum wires, individual wire strands in the cable do not connect well electrically to each other. Additionally, aluminum wire strands in a crimped connection can also deform over time due to stress relaxation and creep. As the aluminum wire in a termination changes shape, electrical resistance can increase causing increased connection resistance, heat build-up, and connector failure. Because of these challenges, conventional crimped connections to aluminum cable constructions with a large number of strands do not provide a robust low resistance connection that will withstand environmental exposure over time. Alternate connection technologies are required to help interconnect each strand in the cable core so they act as a single conductor. It may also be desirable to use existing terminals designed for copper cable connection systems to avoid the expense of designing new terminals made especially for aluminum cable.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.